Now we turn from Boston to that other American region in crisis reeling tonight and asking the nation's prayers. After a massive and mysterious explosion at a fertilizer plant. The image caught on tape the air thick with the smell of ammonia volunteer firefighters overwhelmed. The blast have the ferocity of a two point one earthquake and the thunderous shock. Could be heard 45 miles away. Tonight the small town outside Waco called west has been flattened. ABC's Steve -- and Sami has been there through the night. There moment prices -- families in the small town of west. Texas came at 7:29. PM with a fire raging at their giant fertilizer depot. I don't. A small team of firefighters answering the call worried the whole thing could blow. Then at 753 the sound and no one here it will soon forget. And. Plant blew to pieces. -- -- -- -- upon that went out and it's great. A mushroom cloud of smoke filled the sky. I don't know that -- -- He remembers the and they add up at atomic bombing you know that -- -- Will Ferrell was. By 815 they were at least five firefighters missing two emergency workers killed. The nursing home across the street blasted. And -- my apartment buildings destroyed. At 830 Betty Tucker three blocks down was trapped. And -- a neighbor helped pull her out from under her crumbled walls the most -- have ever heard my. She walked out -- -- wounded neighbors stumbling through the streets doctor set up a makeshift triage and a nearby field. -- -- -- Tonight investigators are trying to determine what started the fire at the plant with its huge tanks of highly flammable and hydrants ammonia. Nitrate fertilizer. We will wait too early in the investigation. To speculate on causes. What may -- actually. -- the timing of the disastrous haunting. Twenty years ago today the compound of the branch Davidian cult and nearby Waco came to a fiery end after a showdown with federal agents. In west tonight -- 160 people are recovering from their injuries. The mayor says up to 45 people are still missing as police searched the rubble for survivors. Late today authorities released the name of the first casualty in this explosion captain Kenny Harris. Who actually worked for the Dallas police Dallas fire department -- lived in west responded to the call -- tonight they're hailing him as a hero.

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